Edel Records -- Nazareth frontman Dan McCafferty apparently is experiencing some more serious health problems. According to U.K. magazine Classic Rock, the band's set at Switzerland's Summerdays Festival on Friday was cut short after the singer reportedly complained of shortness of breath.

A message posted on the website for Belgium's Vosterfeesten event, which Nazareth had been scheduled to headline this past Sunday, reported that McCafferty was in a Swiss hospital "after he suffered a stroke," adding that it was "the second [he'd had] in a short time." The veteran rockers have been forced to cancel additional shows in Germany and Sweden.

Last month, Nazareth canceled most of the dates it had scheduled for a Canadian summer trek after McCafferty collapsed on stage at a July 9 concert in Cranbrook, British Columbia. In addition, earlier this year, the band postponed a series of March U.K. dates after the frontman suffered a chest infection.

Nazareth is best-known for its hard-rock anthem "Hair of the Dog" and for its 1975 rendition of the old Everly Brothers hit "Love Hurts," which reached #8 on the Billboard Hot 100.